We have many members here, and for every 5 members there are probably 7 different answers to this question:
What is your ideal cruise? Heavy on the sea days, or lots of different ports? Huge (3500+ passengers), Large (2000 - 3500), medium (1000 - 2000) or small (less than 1000) ships? Long journey or short hop? Money doesn't matter or every penny counts? One way or round trip? And anything else you can think of.
For me, I would really like to try a round-trip trans-atlantic -- from the US east coast, port in France, Spain and UK and then return. Plenty of sea days, and a total of about 20 days. Not too luxurious (money is a bit limited) but not bargain basement either. Shipboard activities should be there (not a retirement cruise), so something along the lines of RCL. Large or possibly medium size. And definitely in a balcony cabin.
How about you?